Rubber composition and method of preserving rubber



\ '15. all, tertiary aminophenols.

Patented Feb. 1 933 5 m'rrrun w. s

g, Roxanna comrosrtrron: Ann {Human or r ewme v311131 3131;

no D a n This invention relates 'to the preservation of, rubber; and particularly to {the 'prepara tion of rubber compositions" which;resist the deterioration due to aging or to exposure to 5 the atmosphere. It has long been knownth'ait v suchdeterioration canrbe greatly retarded by I v treating the rubber either before or after vulcani z'ation with. certain; substances known I v as ag -regi ters or anti-oxidantsfl Thechief r object of this invention,-then, is to provide a new andsupe'rior class ofanti oxidants' for rubber. a 1 The substances which are employed as anti-oxidants according to this invention are compounds aretho'se in which the two hydrogens of the amino group are substituted by 'alkyl groups p ,7

For example, thefollowing substances are typical members of the class of "anti-oxidants. outlined above: dimethylp aininophenol, d1-- methyl m-aminophenol, diethylf p+aminophen01, I 'diethyl m-aminophenol'," 'd-ipr'opyl; p-am inopheno'l', ,dibutyl p-aminophenoly'diqsopro .pyl p-aminophe'nol; di-i sobutyl p aminophe} nol, 'dibenzyl p-aminophenol, methyl ethyl pa minophenol, methyl benzyl p-aminophenol,

methyl phenyl p-aminophenol, dimethyl am-; inocresol, dimethyl aminonaphthol, dimeth-i ylamino hydroxy biphenyl, tetramethyldi aminophenol, dimethylamino hydroquinone,

dimethylamino guaiacol, p,p'dihydroXy diphenylmethylamine, etc.

- Any one or a mixture of several of the a 3 above-enumerated substances or of other equivalent substances falling Within the same class may be incorporated into rubber With good effect on its age-resisting properties. For example from A to 5% of such ananti-oxidant may be mixed with the rubber before vulcanization; the anti-oxidant: having substantially no accelerating eflect and therefore ordinarily not necessitating an, adjustmeutiof vulcanizing conditions; Alternately, the anti-oxidant may be appliedto tl'lesu'ri ace of crude or vulcanized rubber,

, say in the form of a powder, paste, orsolutioriQ Rubber so treated resists the deteriorating influence of age and exposure to the ele-' The preferred a 'h lieatmirnlea Mar her, T1931. ScriaI'N o 525,870; I I

ments better than, similar untreated rub ber...

i Asa specific example of'one embodiment mm, or. Anon, OHIO; AssIeNoa-ro rim QB. a; eoonarcn COMPANY, or nawxonmn an, A conrona'rron or nawyoax V of the method of this inventioma' t ical 1 tire "tread composition was prepare containing blended plantation rubbers approximatelyxl0O parts by weight, sulfur, 5.'5 parts;

zinc oxide30-parts, gas black 40 p'arts, min-1 m1 rubber 10 parts, palm oil 5* parts; and I hexamethylene' tetramine 0'.'Z5*parts. This ,Was divided into portions to certain of which I wereadded 0.95 parts (0.5% ofthe weight" of the composition) of one ofthe above described anti-'oxidants,"other portions being used as controls The--composit1ons', were thoroughlymixed, and vulcanized in'a press for'45 minutes at 1 t5Gi (249 F.) to produce an optimum 'cure. Therelative rates of aging-{the v vulcanized compositions" were compared; by measuring their respective tensile a strengths and elongations before and afteraging. Acceleratedragingtests were carried; out in the Geer aging oven, in which samples were maintained atI-a temperature of C. a (158 in 'a constantly"'renewed stream of air, as well; as in the Bierer -Davis an atmosphere of oxygen at a pr'egsu -i f 3 00 lbs. per sqJfin; The results of the tests are given in the appended table, in "which T indicates ultimate tenstile strength in pounds per sq; in. and E indicates ultimate elonga tion'in per cent. of original length. 1

i It is evident from the above-examplesfthat rubber; compositions containing even small bomb, in which othersamples were main 1 tainedfiat the sametemperature--;(70 C,)' inother known anti-oxidants,or with other vulcanizing agents than those here specifically disclosed. The proportions of the constituents may be varied, or other substances may be substituted generally therefor, sincethis invention is applicable to pure rubber or rubber compositions of the most varied nature. The anti-oxidants may also be applied to unvulcanized or vulcanized rubber with good effect onthe age-resisting properties of the rubber, such as by applying them to the surface-oi the rubber, as for example in solution, or in the form of a paste or emulsion.

- It is therefore to be understood that the term treating as employed in the appended claims is used in a generic sense toinclude either the incorporation of the antioxidants into the rubber by milling or similar process, or their addition to the rubber latex before its coagulation, or to the application thereof to the surface of a mass of crude or vulcanized rubber. The term rubber is likewise employed in the claims in a generic sense to include caoutchouc, whether natural or synthetic, reclaimed rubber, balata, gutta percha, rubber isomers and like products whether or not admixed with fillers, pigments, vulcanizing or accelerating agents.

lVhile I have herein disclosed certain pre-' ferred manners of performing my invention, I do not therebydesire or intend to limit myself solely thereto, for, as hitherto stated, the precise proportions of the materials utilized may be varied and other materials having equivalent chemicalproperties ma be employed if desired without departing rom the spirit and scope of the invention as defined in the appended claims.

1. The method of preservingrubber which comprises treating rubber with a tertiary aminophenol.

v2. The method of preserving rubber which comprises treating rubber with a dialkyl aminophenol.

3. The methodof preserving rubber which comprises treating rubber with a dialkyl amino hydroxybenzene.

4. The method of preserving rubber which comprises treating rubber with a dialkyl paminophenol.

5-. The methodv of preserving rubber which comprisesftreating rubber with a dialkyl m-aminophenol. V 1 V i 6. The method of preserving rubber which comprises treating rubber with a dialkyl aminophenol in which the alkyl groups are straight chain hydrocarbon groups.

7. The method of preserving rubber which comprises vulcanizing rubber in the presence of; a dialkyl aminophenol.

8. A composition comprising rubber and a tertiary aminophenol.

9. A composition comprising rubber and a dialkyl aminophenol.

10. A composition comprising rubber and a dialkyl amino hydroxy benzene.

11. A composition comprising rubber and a dialkyl p-aminophenol.

12. A composition comprising rubber adialkyl In-aminophenol. I 13. A composition comprisingrubber and a dialkyl aminophenol in which the alkyl groups are straight chain hydrocarbon groups.- i

,14'. A rubber composition which has been vulcanized in the presence of a dialkyl aminophenol. I a 15.. The method of preserving rubber which and comprises treating rubber with dimethyl pamino henol.

16. he method of preserving rubber which comprises treating rubber with dimethyl m-amin'ophenol.

17. The method of preserving rubber which comprises treating rubber with diethyl p-aminophenol.

I 18. A composition comprising rubber and dimethyl p-aminophenol.

19. 'Acomposition comprising rubber and f 

